A Roller Guide and a Method for Guiding Stock

ABSTRACT

A roller guide ( 1 ) for guiding stock in a longitudinal feeding direction (A) toward a pair of rolls for shaping the stock. The roller guide comprises a frame arrangement ( 2 ), a pair of guide rollers ( 3, 4 ) configured to, in a closed position, engage opposite surface portions of the stock,and positioning means for adjusting a lateral distance between the guide rollers. The roller guide further comprises detection means ( 13 ) configured to detect a longitudinal position of a piece of stock ( 20 ) with respect to the guide rollers. The positioning means is configured to adjust the lateral distance between the guide rollers in response to said detection.

TECHNICAL FIELD

The invention relates to a roller guide for guiding stock in a longitudinal feeding direction toward a pair of rolls for shaping the stock according to the preamble of claim 1 and to a method for guiding stock according to the independent method claim. In particular, the invention relates to a roller guide and to a method for use in the production of wire, rods and beams.

BACKGROUND AND PRIOR ART

Roller guides are commonly used for guiding hot stock, such as wire stock or rod stock, in rolling mills. Primarily, roller guides are placed before a pair of rolls used to shape the stock, so called entry roller guides. These roller guides guide the stock which is to be rolled toward a particular rolling groove. The use of roller guides reduces the risk of damaging the stock upon entry between the pair of rolls and enables feeding the stock at high feeding rates.

U.S. Pat. No. 3,935,722 discloses a roller guide for guiding stock toward a pair of rolls. The roller guide comprises a frame arrangement and a pair of guide rollers mounted on the frame arrangement, which guide rollers are configured to engage opposite surface portions of the stock. The guide rollers are rotatable about parallel axes of rotation perpendicular to a longitudinal feeding direction.

Known roller guides further commonly comprise positioning means for adjusting a lateral distance between the guide rollers to be able to accommodate stock of different dimensions. In this case, the lateral distance between the guide rollers is adjusted before operation of the roller guide, and the lateral distance is constant or essentially constant during operation of the roller guide.

Normally, the lateral distance between the guide rollers is set slightly smaller than the lateral dimension of the stock, such that the guide rollers press on the surface portions of the stock. This is necessary to achieve an efficient and accurate guiding of the stock. However, a problem with such known roller guides is that the guide rollers are heavily worn due to the large forces resulting when the stock enters between the guide rollers.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome the above mentioned problem and provide a solution by means of which the forces on the guide rollers are reduced with respect to known solutions.

This object is, according to a first aspect of the present invention, achieved by the roller guide as initially defined. The roller guide is characterized in that it further comprises detection means configured to detect a longitudinal position of a piece of stock with respect to the guide rollers, and that the positioning means is configured to adjust the lateral distance between the guide rollers in response to said detection. By means of the roller guide according to the invention, it is thus possible to automatically adjust the distance between the guide rollers during operation of the roller guide. This enables a reduction of the forces applied to the guide rollers as the stock enters there between. The tool life of the guide rollers can thereby be increased.

According to an embodiment of this aspect of the invention, the positioning means is configured to move the guide rollers between the closed position and an open position, in which the lateral distance between the guide rollers is such as to allow free passage of the stock between the guide rollers. The desired positions of the guide rollers in the open position and the closed position, respectively, can be predefined before operation of the roller guide. By being able to move the guide rollers between a closed position and an open position, it is possible to control the forces exerted by the stock on the guide rollers and vice versa.

According to a preferred embodiment of the invention, the positioning means is configured to move the guide rollers to the open position when no stock is detected between the guide rollers. In this way, the guide rollers are positioned such that the first end of each piece of stock entering the roller guide can pass freely between the guide rollers. Thus, the large forces resulting when the stock enters between the guide rollers are eliminated, and the tool life of the guide rollers is significantly prolonged.

According to another embodiment of the invention, the positioning means is configured to move the guide rollers to the closed position when it is detected that a first end of the piece of stock has passed between the guide rollers. This provides a way to achieve efficient guiding once the piece of stock is already between the guide rollers, without risk of damaging the guide rollers as the first end of the piece of stock enters between them.

According to another embodiment of the invention, the roller guide further comprises primary guiding means configured to guide the stock toward the guide rollers. The primary guiding means are useful for rough guiding of the stock toward the roller guides. Preferably, the primary guiding means are in the form of a guiding funnel which at least partly has the basic shape of a truncated cone.

According to another embodiment of the invention, the roller guide further comprises adjustment means for adjusting the primary guiding means between a guiding position, in which the primary guiding means is configured to guide the stock toward the guide rollers, and a non-guiding position, in which the primary guiding means is configured to allow free passage of the stock through the primary guiding means. Thus, the primary guiding means can be used in the guiding position only when necessary in order to reduce wear on the primary guiding means resulting from contact with the fed stock.

According to another embodiment of the invention, the adjustment means is configured to adjust the primary guiding means to the non-guiding position when a piece of stock is detected between the guide rollers. In this way, the wear on the primary guiding means is minimized, since the stock is allowed free passage as soon as it has entered between the guide rollers. The primary guiding means can for example be adjusted to the guiding position either when it is detected that a rear end of a stock exits the roller guide, or when it is detected that a first end of a stock is approaching the primary guiding means.

According to another embodiment of the invention, the positioning means is in the form of a mechanic, electric, hydraulic or pneumatic positioning means. The hydraulic fluid used in the case of a hydraulic positioning means, as well as the pneumatic fluid used in the case of a pneumatic positioning means, should be a fluid which is suitable for power transfer at the conditions applicable in the roller guide. Mechanic, electric, hydraulic and pneumatic positioning means are able to provide fast and efficient power transfer and are therefore suitable for use in the roller guide, where the travelling speed of fed stock necessitates fast reactions.

According to another embodiment of the invention, the positioning means is servo actuated. This is particularly useful for electric positioning means and provides an excellent position control. For example, the servo actuation enables quick adjustments of the distance between the guide rollers and can be used for pre-adjustment of the lateral distance between the guide rollers, or if applicable of the primary guiding means, as a piece of stock is approaching. Fast adaptations to the dimension of the piece of stock are thereby possible.

According to another embodiment of the invention, the roller guide further comprises sensing means for sensing a force applied by the stock on the roller guide. This is useful since it enables activation of protection measures in the case of unusually high forces applied on the roller guide. One or more force sensors or the like can be used to sense forces at various positions in the roller guide, such as in the primary guiding means or in the guide rollers. The system may be configured such that an error code and/or an alarm signal is generated if the sensing means senses a force exceeding a predetermined threshold level, or a force deviating from an expected level by an amount exceeding a predetermined threshold level.

According to another embodiment of the invention, the positioning means is configured to move the guide rollers in response to a force sensed by the sensing means. The positioning means may e.g. be configured to, in response to a sensed force exceeding a predetermined threshold level, temporarily move the guide rollers. In this way, it is possible to achieve a guiding with a constant or nearly constant force applied on the stock. This provides protection against too high forces applied on the roller guide by the stock and potentially increases the tool durability of the roller guide.

According to another embodiment of the invention, the roller guide further comprises dimension measurement means for determining a dimension of the stock. This is a practical way of obtaining the dimension of the stock and is particularly useful for roller guides placed between successive pairs of rolls in a continuous rolling mill. It is also useful in order to enable adaptation of the lateral distance between the guide rollers in the closed and in the open position, respectively. This can be achieved by arranging the dimension measurement means such that the dimension is measured before the piece of stock enters into the roller guide. In this way, the roller guide can be configured such that the force applied on the stock by means of the guide rollers is always of the same magnitude.

According to another aspect of the present invention, the above mentioned object is achieved by the method as initially defined. The method is characterized in that it comprises the steps:

-   -   detecting a longitudinal position of a piece of stock with         respect to the guide rollers,     -   in response to said detection, adjusting a lateral distance         between the guide rollers.

The advantages of such a method as well as preferred embodiments thereof are apparent from the above discussion relating to the proposed roller guide.

According to an embodiment of this aspect of the invention, when a piece of stock is detected between the guide rollers, the lateral distance between the guide rollers is reduced such that the guide rollers engage said opposite surface portions of the stock.

According to another embodiment of this aspect of the invention, when no piece of stock is detected between the guide rollers, the lateral distance between the guide rollers is increased such that free passage of a first end of a piece of stock between the guide rollers is allowed.

According to another embodiment of this aspect of the invention, wherein the roller guide further comprises primary guiding means configured to guide the stock toward the guide rollers, the method further comprises the step:

-   -   in response to the detection of the longitudinal position of a         piece of stock, adjusting the primary guiding means between a         guiding position, in which the primary guiding means is         configured to guide the stock toward the guide rollers, and a         non-guiding position, in which the primary guiding means is         configured to allow free passage of the stock through the         primary guiding means.

Other advantageous features as well as advantages of the present invention will appear from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will in the following be further described by means of example with reference to the appended drawings, wherein

FIG. 1 shows a schematic view of a roller guide according to an embodiment of the invention in a first position,

FIG. 2 shows the roller guide of FIG. 1 in a second position,

FIG. 3 shows the roller guide of FIG. 1 in a third position, and

FIG. 4 shows the roller guide of FIG. 1 in a fourth position.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

A schematic illustration of a roller guide 1 according to an embodiment of the present invention is shown in FIG. 1-4. The roller guide 1 is intended for guiding stock in a longitudinal feeding direction A in a rolling mill, primarily toward a pair of rolls for shaping the stock. The roller guide 1 comprises a frame arrangement 2 and a pair of guide rollers 3, 4, each guide roller 3, 4 being mounted on an arm 5, 6 of the frame arrangement 2. The arms 5, 6 are pivotable and movable such that a lateral distance, i.e. in a direction perpendicular to the feeding direction A, between the guide rollers 3, 4 can be adjusted. The guide rollers 3, 4 are rotatable about parallel axes of rotation C3, C4 perpendicular to the longitudinal feeding direction A and to the lateral direction. The roller guide 1 further comprises a control unit 7 in which positioning means for adjusting the lateral distance between the guide rollers 3, 4 by means of moving and pivoting the arms 5, 6 is comprised.

Detection means 13 for detecting that a first end 20 a of the piece of stock 20 is approaching the guide rollers 3, 4 is provided on the inside of the guiding part 11. The roller guide further comprises primary guiding means 9 configured to guide the stock toward the guide rollers 3, 4. In the shown embodiment, the primary guiding means 9 is in the form of a guiding funnel comprising an entry funnel 10 and two guiding parts 11, 12. Adjustment means for adjusting the primary guiding means 9 between a guiding position, in which the primary guiding means 9 is configured to guide the stock toward the guide rollers 3, 4, and a non-guiding position, in which the primary guiding means is configured to allow free passage of the stock through the primary guiding means 9, is provided in the control unit 7.

FIG. 1 shows the roller guide 1 before entry of a piece of stock 20 into the roller guide 1. The guide rollers 3, 4 are positioned after the primary guiding means 9 in the longitudinal feeding direction

A. The control unit 7 comprises positioning means (not shown) for moving the guide rollers 3, 4 and adjustment means (not shown) for adjusting the position of the guiding parts 11, 12 of the primary guiding means 9. In the position shown in FIG. 1, the primary guiding means 9 are in the guiding position. In other words, the guiding parts 11, 12 are positioned close to each other such that a narrow channel for guiding the piece of stock 20 between the guiding parts 11, 12 is formed. The guide rollers 3, 4 are in an open position, in which the lateral distance between the guide rollers 3, 4 is sufficiently large to allow free passage of the piece of stock 20 without physical interaction with the guide rollers 3, 4.

In FIG. 2, the piece of stock 20 has entered into the primary guiding means 9 of the roller guide. The primary guiding means 9 is still in the guiding position and the guide rollers 3, 4 are in the open position. The first end 20 a of the piece of stock 20 has just passed the detection means 13. A signal is sent from the detection means 13 to the control unit 7 comprising the positioning means and the adjustment means. The positioning means and the adjustment means are thereby activated.

In FIG. 3, the positioning means has moved the guide rollers 3, 4 from the open position to a closed position, with a decreased lateral distance between the guide rollers 3, 4, and the front end 20 a of the piece of stock 20 has passed between the guide rollers 3, 4. The adjustment means has moved the primary guiding means 9 to the non-guiding position by increasing the lateral distance between the guiding parts 11, 12. The guide rollers 3, 4 thus engage opposite surface portions of the piece of stock 20 and thereby apply a guiding force, while free passage is allowed through the primary guiding means 9.

In FIG. 4, the entire piece of stock 20 has passed between the guide rollers 3, 4. This has been detected by the detection means 13. The primary guiding means 9 has been moved to the guiding position by reducing the lateral distance between the guiding parts 11, 12. The guide rollers 3, 4 have been moved to the open position. The roller guide 1 is thereby ready to receive another piece of stock.

In order to determine that the first end 20 a of the piece of stock 20 has passed between the guide rollers 3, 4, means for measuring or estimating the travelling speed of the piece of stock 20 may be provided on the guide roller 1. Information about the travelling speed may also be obtained from some other, external source. Alternative ways of determining that the first end 20 a has passed between the guide rollers 3, 4 include placing a detector on the level of the guide rollers 3, 4 or just after the guide rollers 3, 4 in the feeding direction.

The positioning means and the adjustment means may be comprised in the same control unit as shown above, but may also be controlled separately. The positioning means and the adjustment means may be mechanic, electric, hydraulic or pneumatic and may be servo actuated. In the shown embodiment, the positioning means are configured to effect adjustment of the lateral distance between the guide rollers 3, 4 by means of pivoting and displacing the arms 5, 6 on which the guide rollers 3, 4 are mounted. However, the positioning means may instead be configured to effect adjustment of the lateral distance by lateral displacement only, without pivoting action.

The guide roller 1 is preferably displaceable in the lateral direction, for example along a guiding track, such that it can be used to guide stock toward different rolling grooves of a pair of rolls placed after the roller guide.

Sensing means for sensing a force applied by the stock on the roller guide 1, such as a force sensor, e.g. in the form of a strain gage placed on one or both arms 5, 6, is preferably provided on the roller guide 1. The force sensor can be used for overload protection and should therefore preferably be connected to the positioning means. In case the force sensed by the force sensor exceeds a predetermined threshold, protection measures are activated. For example, the lateral distance between the guide rollers 3, 4 can be temporarily increased, or the tension from the positioning means, keeping the guide rollers 3, 4 in the closed position, can be temporarily released. If the force sensed by the force sensor exceeds the threshold, an alarm signal may be generated to alert an operator of the roller guide.

The positioning means are preferably configured such that the stock is guided at a constant load, i.e. so that the force applied by the guide rollers on the stock is constant, or nearly constant, when the guide rollers are in the closed position. The closed position may therefore not be static in terms of lateral distance between the guide rollers, but may be defined as a certain force applied by the guide rollers on the stock.

The roller guide may also comprise dimension measurement means for determining a dimension of the stock and means for measuring vibrations.

The invention is of course not in any way restricted to the embodiments described above, but many possibilities to modifications thereof would be apparent to a person with skill in the art without departing from the scope of the invention as defined in the appended claims. 

1. A roller guide (1) for guiding stock in a longitudinal feeding direction (A) toward a pair of rolls for shaping the stock, the roller guide (1) comprising: a frame arrangement (2), a pair of guide rollers (3, 4) mounted on the frame arrangement (2), which guide rollers are configured to, in a closed position, engage opposite surface portions of the stock, the guide rollers (3, 4) being rotatable about parallel axes of rotation (C3, C4) perpendicular to the longitudinal feeding direction (A), and positioning means for adjusting a lateral distance between the guide rollers (3, 4), wherein the roller guide further comprises detection means (13) configured to detect a longitudinal position of a piece of stock (20) with respect to the guide rollers (3, 4), and that the positioning means is configured to adjust the lateral distance between the guide rollers (3, 4) in response to said detection.
 2. The roller guide (1) according to claim 1, wherein the positioning means is configured to move the guide rollers (3, 4) between the closed position and an open position, in which the lateral distance between the guide rollers (3, 4) is arranged to allow free passage of the stock between the guide rollers (3, 4).
 3. The roller guide (1) according to claim 2, wherein the positioning means is configured to move the guide rollers (3, 4) to the open position when no stock is detected between the guide rollers (3, 4).
 4. The roller guide (1) according to claim 1, wherein the positioning means is configured to move the guide rollers (3, 4) to the closed position when it is detected that a first end of the piece of stock (20) has passed between the guide rollers (3, 4).
 5. The roller guide (1) according to claim 1, wherein the roller guide (1) further comprises primary guiding means (9) configured to guide the stock toward the guide rollers (3, 4).
 6. The roller guide (1) according to claim 5, further comprising adjustment means for adjusting the primary guiding means (9) between a guiding position, in which the primary guiding means (9) is configured to guide the stock toward the guide rollers (3, 4), and a non-guiding position, in which the primary guiding means (9) is configured to allow free passage of the stock through the primary guiding means (9).
 7. The roller guide (1) according to claim 6, wherein the adjustment means is configured to adjust the primary guiding means (9) to the non-guiding position when a piece of stock (20) is detected between the guide rollers (3, 4).
 8. The roller guide (1) according to claim 1, wherein the positioning means is in the form of a mechanic, electric, hydraulic or pneumatic positioning means.
 9. The roller guide (1) according to claim 1, wherein the roller guide (1) further comprises sensing means for sensing a force applied by the stock on the roller guide (1).
 10. The roller guide (1) according to claim 9, wherein the positioning means is configured to move the guide rollers (3, 4) in response to a force sensed by the sensing means.
 11. The roller guide (1) according to claim 1, further comprising dimension measurement means for determining a dimension of the stock.
 12. A method for guiding stock in a longitudinal feeding direction (A) toward a pair of rolls for shaping the stock, wherein a roller guide (1) is used, the roller guide (1) comprising: a frame arrangement (2), a pair of guide rollers (3, 4) mounted on the frame arrangement (2), which guide rollers (3, 4) are configured to, in a closed position, engage opposite surface portions of the stock, the guide rollers (3, 4) being rotatable about parallel axes of rotation (C3, C4) perpendicular to the longitudinal feeding direction (A), wherein the method comprises the steps: detecting a longitudinal position of a piece of stock (20) with respect to the guide rollers (3, 4), and in response to said detection, adjusting a lateral distance between the guide rollers (3, 4).
 13. The method according to claim 12, wherein, when a piece of stock (20) is detected between the guide rollers (3, 4), the lateral distance between the guide rollers (3, 4) is reduced such that the guide rollers (3, 4) engage said opposite surface portions of the stock.
 14. The method according to claim 12, wherein, when no piece of stock (20) is detected between the guide rollers (3, 4), the lateral distance between the guide rollers (3, 4) is increased such that free passage of a first end (20 a) of a piece of stock (20) between the guide rollers (3, 4) is allowed.
 15. The method according to claim 12, wherein the roller guide further comprises primary guiding means (9) configured to guide the stock toward the guide rollers (3, 4), the method further comprising the step: in response to the detection of the longitudinal position of a piece of stock (20), adjusting the primary guiding means (9) between a guiding position, in which the primary guiding means (9) is configured to guide the stock toward the guide rollers (3, 4), and a non-guiding position, in which the primary guiding means (9) is configured to allow free passage of the stock through the primary guiding means (9).
 16. The roller guide (1) according to claim 3, wherein the positioning means is configured to move the guide rollers (3, 4) to the closed position when it is detected that a first end of the piece of stock (20) has passed between the guide rollers (3, 4).
 17. The roller guide (1) according to claim 2, wherein the positioning means is configured to move the guide rollers (3, 4) to the closed position when it is detected that a first end of the piece of stock (20) has passed between the guide rollers (3, 4).
 18. The roller guide (1) according to claim 17, wherein the roller guide (1) further comprises primary guiding means (9) configured to guide the stock toward the guide rollers (3, 4).
 19. The roller guide (1) according to claim 16, wherein the roller guide (1) further comprises primary guiding means (9) configured to guide the stock toward the guide rollers (3, 4).
 20. The roller guide (1) according to claim 4, wherein the roller guide (1) further comprises primary guiding means (9) configured to guide the stock toward the guide rollers (3, 4). 